Formulation and Evaluation of Bilayer Tablets of Sustained Release Pregabalin and Immediate Release Methylcobalamin

Neuropathic pain is intense in nature and difficult to maintain. The main aim of this study is to provide maximum relief from pain.  The objective was to prepare bilayer tablet comprising  of pregabalin and methylcobalamin for effective treatment of neuropathic pain. Methylcobalamin was formulated as immediate release (IR) layer using super-disintegrant sodium starch glycolate (SSG) whereas pregabalin was formulated as sustained release (SR) layer using polymers hydroxypropyl methyl cellulose (HPMCK4M, K100M)  to deliver the drug at sustained manner effective for the treatment of neuropathic pain. The SR layer of pregabalin is prepared by wet granulation method and IR layer of methylcobalamin is prepared by direct compression method. Tablet blends were evaluated through various pre-compression and post-compression tests. Super disintegrant, SSG at 20% concentration produced excellent results for immediate release of methylcobalamin to exert its action and other additional beneficial effects. The K100M and K4M grade of HPMC produced excellent SR efficiency. Optimum formulation released methylcobalamin and pregabalin at 98.92%  in 45 min and 97.81% in 12 h from respective layers. Pre-compression and post-compression parameters of optimized IR layer comprising Methylcobalamin and SR layer comprising pregabalin exhibit satisfactory results. Bilayer tablet of Methylcobalamin and pregabalin prove to be effective as a combination therapy for the treatment of neuropathic pain by sequential release of the drug.